/Engine/Source/Runtime/Engine/Classes/Particles/ParticleSystemComponent.h
Collision Handling...
virtual bool ParticleLineCheck ( [FHitResult](API\Runtime\Engine\Engine\FHitResult) & Hit, [AActor](API\Runtime\Engine\GameFramework\AActor) * SourceActor, const FVector & End, const FVector & Start, const FVector & HalfExtent, const [FCollisionObjectQueryParams](API\Runtime\Engine\FCollisionObjectQueryParams) & ObjectParams )